1. Field of Invention
The present invention relates to a system for reprogramming a monitor function. More particularly, the present invention relates to a monitor control system that utilizes the video graphic adapter (VGA) signal lines of a VGA card to reprogram a monitor function.
2. Description of Related Art
In the current most monitor systems, the monitor controller must be changed whenever monitor functions need to be modified or software bugs need to be removed. The process is laborious and wasteful. For more advanced monitor systems, the monitor systems usually have built-in read-only-memory (ROM) of the erasable programmable type. By modifying the internal data inside the erasable programmable ROM, modification of monitor function or correction of software bugs can be easier done.
FIG. 1 is a block diagram showing the circuit connections of various elements in a conventional programmable monitor system. The monitor is connected to a VGA card via a set of eight VGA signal lines 18. The VGA signal lines 18 include a vertical synchronous signal line (Vsync), a horizontal synchronous line (Hsync), a serial data line (SDA), a serial clock line (SCL), a ground (Gnd), a red R, a green G and a blue B line. In normal operation, a first jumper 14 is set such that the horizontal & vertical deflector 20 is connected to a monitor controller 10. In the meantime, a second jumper 16 is set such that an on-screen display 50 is also connected to the monitor controller 10. In addition, a power jumper 12 is set such that 5V are applied to the monitor controller 10. Signal lines Hsync, Vsync, SDA, SCL and Gnd are coupled to the monitor controller 10. The horizontal & vertical deflector 20 is driven according to the signals received through the signal lines and the programs stored inside the ROM unit of the monitor controller 10. The horizontal & vertical deflector 20 in turn controls a vertical booster 30 and a horizontal booster 40 so that an electronic beam is able to sweep horizontally and vertically inside a cathode ray tube (CRT). At the same time, the monitor controller 10 also drives the on-screen display 50. The on-screen display 50 controls an image pre-amplifier 60 for receiving red R, green G and blue B signals from the R, G and B lines. After passing through the pre-amplifier 60, signals are transferred to an image amplifier 70 for display on screen.
With the monitor system as shown in FIG. 1, any functional modification can be achieved by modifying the data inside the ROM unit of the monitor controller 10. However, before stored data inside the ROM unit can be changed, the monitor must be opened up and the first jumper 14 and the second jumper 16 must be reset. The jumpers 14 and 16 must be set such that the monitor controller 10 is connected to an erase/record socket 80 and the power jumper 12 is connected to a 12V input voltage. A ROM writer (not shown in the figure) is plugged into the erase/record socket for reprogramming the functions inside the monitor system.
FIG. 2 is a schematic view showing the connection of a conventional monitor system with a memory erase/record system. After the external casing of the monitor 100 is taken off, a main circuit board 110 is revealed. An erase/record socket 80 and a set of VGA signal lines 18 are laid on the circuit board 110. The first jumper 14, the second jumper 16 and the power jumper 12 are found within a jumper area 22. The memory erase/record system 90 includes a ROM writer 92, a computer system 94 and a programming monitor 96. The computer system 94 controls all the operations of the ROM writer 92. Programming status of the operation can be observed through the programming monitor 96. When the ROM writer is plugged into the erase/record socket 80 of the main circuit board 110, memory inside the monitor can be reprogrammed by the computer 94 so that a different monitor function can be used.
In brief, the external casing of a conventional monitor must be taken off and a set of jumpers must be switched before reprogramming can start, which is a laborious and inconvenient process.